Chitosadcalcium-alginate beads were prepared by a coacervation method in aqueous medium. Their swelling properties and morphologies were studied. Complexed beads with a mean diameter of 500 pm were obtained by dropwise addition of a sodium alginate solution into a chitosan-calcium chloride solution. From scanning electron microscopic studies, we observed that chitosan modifies the morphology of calcium-alginate beads. The swelling properties of chitosadcalcium-alginate beads are different from those of calcium-alginate beads. In the case of calcium-alginate beads, the swelling volume increases as the pH of the medium increases. However, chitosadcalcium-alginate beads show a maximum swelling volume at pH 9.0.
In this study, we prepared polymer micelles containing quercetin and rutin, known as antioxidants, using poly(ε-caprolactone)-b-poly(ethylene glycol), and evaluated in vitro skin permeation of the active materials. Quercetin and rutin loaded micelles were characterized by DSC (differential scanning calorimetry), HPLC (high performance liquid chromatography) and DLS (dynamic light scattering) measurements. The particle size of the polymer micelles increased in a concentration dependent manner (0.5~2.0% PCL-b-PEG). The Zeta potential of quercetin and rutin loaded micelles remained constant. To evaluate the skin penetration of PCL-b-PEG micelles, Franz diffusion cell experiment was performed. The aqueous solutions of quercetin and rutin were used as the control groups. Quercetin and rutin loaded PCL-b-PEG micelles showed more efficient skin permeation than the control groups. Safety assessment (patch test) of quercetin and rutin loaded PCL-b-PEG micelles on skin was performed to test application possibility of the polymer micelles to cosmetics. Any adverse symptoms were not observed.
− Thermogravimetric analysis(TGA) was carried out for pyrolysis and char-CO 2 gasification of low rank Indonesian ABK coal and China lignite. The pyrolysis rate was successfully described by a two-step model adopting the modified Kissinger method. The shrinking core model, when applied to char-CO 2 gasification gave initial activation energy of 189.1 kJ/mol and 260.5 kJ/mol for the ABK coal and China lignite, respectively. Thus, the char-CO 2 gasification has been successfully simulated by the shrinking core model. In particular, the activation energy of char-CO 2 gasification calculated in this work is similar to the results on the anthracite coal, but considerable difference exists when other models or coal types are used.
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